We present a detailed study of the critical current density of YBa
2Cu
3O
7−
δ
thin films grown by pulsed laser deposition. Among the salient features are the total absence of any traits ...characteristic for pinning by extended linear defects, and an unexpected increase of the critical current density with film thickness. It turns out that critical current the dependence of critical current density on thickness is correlated with the field dependence of the same quantity; thicknesses of the both are very well described by extending to finite film thickness the Ovchinnikov–Ivlev theory of strong pinning Phys. Rev. B 43 (1991) 8024.
Transport properties of Nb/CuMn multilayers with a regular array of antidots have been measured at different temperatures in the presence of external perpendicular magnetic fields. Two series of ...samples, which differ for the Mn percentage, for the diameter, and for distance of the antidots have been analyzed. In both the series, hysteresis in current-voltage characteristics has been observed, which disappears when approaching the upper critical magnetic field. We have related the onset of this hysteresis to the presence of an irreversibility line in the H-T plane, due to the quantum melting of the vortex lattice.
We present a detailed study of the critical current density of YBa sub(2)Cu sub(3 )O sub(7- delta ) thin films grown by pulsed laser deposition. Among the salient features are the total absence of ...any traits characteristic for pinning by extended linear defects, and an unexpected increase of the critical current density with film thickness. It turns out that critical current the dependence of critical current density on thickness is correlated with the field dependence of the same quantity; thicknesses of the both are very well described by extending to finite film thickness the Ovchinnikov-Ivlev theory of strong pinning Phys. Rev. B 43 (1991) 8024. copyright 2001 Elsevier Science B.V. All rights reserved.
A peak in the resistance versus temperature measurements, just above T sub c , has been observed in Nb/CuMn multilayers with a regular array of holes. The peak is present in zero magnetic field and ...its height becomes smaller as the perpendicular field is increased. The presence of the peak could be related to the nonhomogeneity of the sample consistently giving an explanation for the upward curvature observed in the H sub c2 versus temperature curve.
Vortex lattice melting in perforated Nb/(Cu-Mn) multilayers Attanasio, C.; di Luccio, T.; Mercaldo, L. V. ...
Philosophical magazine. B, Physics of condensed matter. Structural, electronic, optical, and magnetic properties.,
05/2000, Letnik:
80, Številka:
5
Journal Article
We report the results of transport measurements in perforated superconducting (Nb)-spin-glass (Cu-Mn) multilayers. Current-voltage (I - V) characteristics were measured as a function of the ...temperature T, magnetic field H and sample anisotropy
γ
0
. The noise and the hysteresis in the I-V curves were observed only for certain values of temperature and magnetic field, dependent on the anisotropy value. Outside these values both the noise and the hysteresis vanished. Among the possible mechanisms responsible for this, the quantum melting of the vortex lattice seems to be the most appropriate in describing the experimental data. The dynamic phase diagram is reproduced for samples with different anisotropies.
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